两株凯伦藻对轮虫急性毒性的研究

本实验初步研究了两株凯伦藻Karenia selliformis和Karenia umbella对褶皱臂尾轮虫（Brachionus plicatilis）的毒性效应。通过设置不同浓度的藻细胞培养液，在48 h内对褶皱臂尾轮虫进行急性毒性观察试验，研究结果表明，K.selliformis和K.umbella对褶皱臂尾轮虫具有明显的毒性作用。在短时间内（2 h），两种凯伦藻的毒性效应均与细胞密度呈现较好的正相关性（K.selliformis，R2=0.96；K.umbella，R2=0.92）。对轮虫2 h的半致死浓度（LD₅₀）分别为2750/mL（K.selliformis）和14011/mL（K.umbella），显示K.selliformis对褶皱臂尾轮虫的急性毒性作用较之K.umbella更强。通过进一步比较两种凯伦藻的藻液、细胞过滤液和藻细胞破碎液的毒性结果显示，仅藻液有毒害作用，而去细胞过滤液和藻细胞破碎液对轮虫没有毒害作用，说明与藻细胞的直接接触是导致轮虫死亡的关键因素。

Study on acute toxicity of two Karenia (Dinophyceae) species to rotifer Brachionus plicatilis

The toxicity effect of Karenia species (Karenia selliformis and Karenia umbella) on rotifer Brachionus plicatilis has been studied. The results showed that two strains of K. selliformis and K. umbella had significant toxic effect on B. plicatilis. The toxicities of the two species were positively correlated with cell density in a short test time (2 hours), with a coefficient (R2) of 0.96 and 0.92, respectively. The 2 h LD₅₀ of K. selliformis and K. umbella on B. plicatilis was 2750/mL and 14011/mL, respectively, indicating a more intense toxicity of K. selliformis. Comparison of the toxicity of different algal fractions (culture cells, filtrate and broken cells) showed that culture cells had intense effects, while the filtrate and broken cells of both species have no toxicity on B. plicatilis. The direct contact with culture cells is to be one of the key factors that resulted in the deaths of rotifers.